Process and means for preventing one of two centrifugally-separated liquids from contaminating the other



Feb. 26 1924. 1,485,177

E. A. FORSBERG PROCESS. AND MEANS FOR PREVENTING ONE OF TWOCENTRIFUGALLY SEPARATED LIQUIDS FROM CONTAMINATING THE OTHER Filed Oct.20 1923 W/T/VESS. I //V VE/V 7-01? Er/ fluyasf Forsbery av Patented Feb.26, 1924.

UNITED 'sr-Aras PATENT orrlcn.

ERIK AUGUST FOBSBEBG, STOOKHOLM, SWEDEN, ASSIGNOR- TO THE DE LAVALSEPABATOR COMPANY, 01!? NEW YORK, N. Y., A CORPORATION OF NEW JERSEY.

PROCESS AND MEANS FOR PREVENTING- ONE 0]? TWO 'OENTBIFUGALLY-SE PARATELIQUIDS FROM CONTAMINATING THE OTHER.

Application filed October 20, 1923. Serial No. 669,655.

To all whom it may concern:

Be it known that I, ERIK AUGUST Fonsnnnc, a subject 'of the King ofSweden, residing at Stockholm, Sweden, have invented a new and usefulImprovement in'Processes and Means for Preventing One of TwoCentrifuga'lly-Separated Liquids from Contaminating the Other, of whichthe following is a full, clear, and exact description, reference beinghad to the accompanying drawings, which form a part of thisspecification.

In the centrifugal separation of a liquid from a contaminating liquid ofdifferent spe cific gravity, whether or not they are admixed with solidimpurities, it is possible, with the most nearly perfected typeof .centrifuge, to effect a practically complete separation within the bowl ofthe liquid that it is desired to recover in a pure condition and todischarge the liquid in that condition from the bowl outlet. Heavy solidimpurities will be retained on the'inner wall of the bowl until theseparating operation is finished,

. but it is nearly always desirable to provide the bowl with a separateoutlet for the continuous disch'arge of the contaminating liquid, andthat is always imperative if the total volume of mixed li uid is largeor if the contaminating liqui. is present in a considerable proportion.During the discharge of the two liquids from their respective outlets,the difliculty arises that there is a tendency for a small proportion ofthe contaminating liquid to remix with theother liquid. This tendencywill be more readlly understood by explaining, in general, theconstruction of a typical bowl and its receiving pans. It will beassumed, in this explanation, that it is sought to dehydrate transformeroil or switch oil, which are examples of liquids which must be purifiedto an almost absolute degree and which, there'- fore, cannot besuccessfully treated by the centrifugal separation process 1f there sany appreciable remixing of water with 011 during the discharge of thetwo liquids.

A t its heiiiiier liquiddischarge outlet (in the case assumed, the wateroutlet) near the top of the bowl just below its neck and relativelydistant from the axis of rotation. The lighter liquid discharge outlet(in the case assumed, the oil outlet) is located in the neck icaltwo-outlet centrifugal bowl has of the bowl above the water outletand'rela tively near the axis of rotation. There is usu'ally a third, oroverflow, outlet at the top of the neck of the bowl. Surrounding, theupper part and neck of the bowl are a corresponding number of covers orreceiving pans'or receptacles. In the construction assumed, there wouldtherefore be three receptacles: a lower one for the water, amiddle onefor. the oil and an upper one to receive any overflow in' case the bowlshould become loaded beyond its capacity. The

pans, which are stationar are necessarily provided with central ori cesof greater diameter than the parts of the bowl that they respectivelysurround leaving an annular space between the bowl and each pan.

7 Assuming that the bowl is functioningefficiently, when oil dischargesfrom the bowl and streams, across theannular space mentioned, into theoil receptacle, it is practically free from water. A. short distancebelow-the oil discharge, water is simultaneously streaming into thewater receptacle. It is clear that if even a very'small proportion ofwater in this discharging stream mixes with the discharging stream ofoil,

vthe oil will not pass into the oil receptacle in a completelydehydrated condition. This remixing does actually occur. The explanationof the phenomenon is thatthe water is discharged in finely divided dropsor particles which remain suspended in the air and also that the airitself becomes saturated 'with dissolved moisture.

Means Have been devised with the object in view of preventing "finedrops of water suspended in the air from getting into the oilreceptacle, and certain of such means have been fairly effective. It maybe questioned, however, whether such means ever prevent the finest waterparticles from being carried by the air whirls into the oil stream; andit is certain that such means do not prevent moisture dissolved in theair from rising'to the discharging oil stream and there being caught bythe dischargingl oil, especially as the latter is partly in t e form ota very fine spray. v

The present invention is designed to effectually prevent any water,either in the form of drops or particles or discharged into thedischarge spouts of the stationary receptacle that receives the oildischarged from the bowl, and the object is accomplished: first, bydeterring the passage of water in any form from the water discharge ofthe bowl to the oil discharge thereof; secondly, by preventing theprecipitation in the oil of water or moisture that is in the immediatevicinity of the stream or spray of oil that is being discharged from thebowl; and thirdly, removing from the oil, as it is sprayed from the oildischarge into the receptacle, any suspended, adhering, or precipitatedwater or-moisture that is carried by the oil spray toward or into thereceiving space of the receptacle: thereby preventing any water frombeing carried with the oil out of the receptacle intothe ultimatereceiver for the oil. The invention is also applicable to the process ofseparating w'ater from liquids other than oil and may be foundapplicable to the separation of other liquids of different specificgravities.

In the drawings:

Fig. 1 is a vertical sectional view illustrating a centrifugal bowl, itshousing, the receiving pans and a preferred embodiment of of whichexcept the lowest forms the top or cover of one receptacle and each oneof which except the highest forms the bottom of one receptacle; therebyforming three receptacles, one, f, for water, another, 9, for oil, and athird, h, for overflow. The re- .eptacles are provided respectively withthe uiSChaIge spouts 2', j and k. The above described construction andarrangement are old and customary.

Referring to Fig. 1, a tube m extends 1nto the discharge spout 7', itsopen end terminating approximately above the central opening of the panbeneath the oil discharge (lighter liquid outlet) of the bowl. Throughthis tube heated air is blown. A convenient means of creating a draft ofheated air comprises a fan n and an electric heater 0 through whichatmospheric air is successively conveyed into the tube m. The current ofair blown out of the tube m spreads itself within the central part oftheoil receptacle. Inasmuch as heated air has a greater capacity forabsorbing moisture than cold air, the saturating degree of moisture ofthe air in theoil receptacle is reduced and thus any small drops ofwater that are SUS- pended in the air are vaporized and dissolved by theair. Any water that may adhere to the oil is vaporized and dissolved bythe air. The heated air has thus a pro: nounced drying or dehydratingeffect on the oil. The action of the heated air is very intensive byreason of the fact that both the water and oil are discharged from thebowl in a very finely divided form. The heated air outflows down towardthe Water discharge from the bowl or up past the overflow discharge orin both directions; any flow of heated air toward the water dischargetending to prevent the passage of water in an opposite direction andtherefore deterring an initial mixing of water with the oil spray.

A permissible modification is shown in Fig. 2, in which a tube ;0extends into the oil receptacle and is formed therein into a coil.Through this tube and coil circulates a heating medium, such as hotWater or steam. It will be understood that the rotation of the-bowl hasan effect upon the surrounding air similar to that of a fan orrotatingventilator, thereby tending to'di splace the air from the housing anddraw in air through the several spouts and receptacles and down aroundthe bowl neck into the space within the housing. Air inflowing throughthe spout directly contacts with the'heated tube 7) and is heated by thetime it approaches the stream of oil being discharged from the bowl andtherefore acts in a similar manner to the hot air blown out of the tubem in Fig. 1.

The characteristic feature of the invention is the production of acurrent of air, at a temperature substantially higher than that of thesurrounding air, into the vessel that collects the separated liquid,such as oil, which it is desired to recover in a pure condition, so asto prevent the precipitation of any unprecipitated contaminating liquid,such as water, that, escaping from its separate discharge, has remixedwith the oil, and also to absorb any contaminating liquid that may havebeen precipitated.

It is clear that the invention is not limited to the specific meansshown and described, and it is also clear that the process is notdependent, for its successful execution, upon the employment of anyparticular means for facilitate its outflow through the discharge spout.In this process, however, the exclusion of minute quantities of oil fromthe discharging wax is of little or no im'porthe process of preventing,

tance and the steam jacket is applied to the receptacle for receivingthe liquid (wax) discharged from the heavier liquid outlet from thebowl.

Having now fully described my invention, what I claim and desire toprotect by Letters Patent is: i

1. In the centrifugal separation of water from a liquid of different secific gravity, the process of preventing, after such separation, thecontamination of such liquid discharging from the separating bowl by thedischarging water, which comprises creating a flow of heated air in theneighborhood of the locus of discharge of said liquid from the bowl,thereby tending to prevent the precipitation of water in the liquid andto effect the dehydration of any part of the liquid to which water hasadhered.

2. In the centrifugal separation of water from a liquid of differentspecific gravity, after such sepa ration, the contamination of suchliquid discharging from the separating bowl by the discharging water,which comprises creating a flow of heated air toward and past the locusof discharge of such liquid from the bowl, thereby tending to preventthe precipitation of water in the liquid and to dry any liquid in whichwater has been precipitated and also by reason of the direction of flowof the heated air, deterring the passage' into the stream of liquiddischarging from the bowl of water that has discharged therefrom.

3. In the centrifugal separation of water from a liquid of difl'erentspecific gravity, the'process of preventing, after such separation, thecontamination of such liquid discharging from the centrifugal bowl bythe discharging water, which comprises creating a draft of air towardthe locus of discharge of said liquid from the bowl and; heating saidair before it reaches said locus.

4. In a centrifugal apparatus, the combination of a rotary vided with aplurality of discharges for liquids of difierent specific gravities, aresepara ting bowl proceptacle surrounding the bowl and positioned toreceive the liquid discharged from the bowl which it is desired torecover in a pure condition, means creating a flow of airthrough saidreceptacle toward the oor responding bowl discharge, and means to heatsaid air. q

5. In a centrifugal apparatus, the combination of a rotary separatingbowl pro.- vided with an upper outlet for the discharge of the lighterseparated liquid and a lower outlet for the discharge of the heavierseparated liquid, receptacles, one over the other, positioned to receivethe liquids delivered from the respective bowl discharges, and means tosubstantially raise the temperature of the air surrounding the stream ofliquid being delivered from the upper bowl outletinto the upperreceptacle.

6. In a centrifugal apparatus, the combination of a rotary separatingbowl provided with an upper outlet .for the discharge of thelightersepara-ted liquid and a lower outlet for the discharge of theheavier separated liquid, receptacles, one over the other positioned toreceive the liquids delivered from the respective bowl discharges, meanscreating a How of air through the u per.

receptacle toward the corresponding owl outlet, and means to heat saidair.

7. In a centrifugal apparatus, the combination of a rotaryseparating'bowl pro vided with a plurality of discharges for liquids ofdifl'erent specific gravities, a receptacle surrounding the bowl andpositioned to receive the liquid delivered from one'of said discharges,a pipe entering said receptacle, said pipe opening in the neighborhoodof the stream of liquid discharging from the bowl into said receptacle,means to blow air through said pipe and out said opening, and means toheat the air blown through said pipe.

In testimonyof which invention, I have hereunto set .my hand, atStockholm, on this the 4th day of October, 1923.

ERIK AUGUST FORSBERG,

